This invention relates to a riveting device for the assemblage of two or more sheet metal sections of a structure.
In particular, the invention concerns a riveting device of the above type comprising a percussive riveting tool arranged to operate on one side of said sections, an inertia bucking means located on the opposite side of said sections and being applicable against the rivets being worked by said riveting tool, a first clamping means applicable against said sections on the same side as said riveting tool, a second clamping means applicable against said sections on the same side as said inertia bucking means, and a means for locating said riveting tool and said inertia bucking means as well as said first clamping means and said second clamping means in various working positions on the sections to be assembled.
A problem inherent in previous rivet bucking devices of the above type resides in the fact that the impacts delivered to the rivets by the percussive riveting tool are transferred also to the structure sections to be assembled and that these tend to be deformed in the area around each rivet. The reason is that the percussive riveting tool is arranged to direct its blows onto the head of the rivet, whereas the inertia bucking means is applied on the rivet shaft to be upset. This is to ensure that the rivet head is firmly seated against the sections to be assembled. If the tools were arranged the other way around it might occur that the rivet head would be slightly separated from the surface of the work piece as a direct result of the blows of the riveting hammer.
For each blow of the riveting hammer onto the rivet head the rivet and that part of the sheet metal sections that closely surrounds the rivet are displaced a distance corresponding to the rate of deformation of the rivet shaft accomplished at each blow. Thereat, the rivet and the sheet metal portion around the rivet are exposed to a very high acceleration in the direction toward the bucking means: This acceleration amounts to 10, 000-20, 000 m/s.sup.2.
Since the clamping means of previous riveting devices possess a considerable, inertial mass, the acceleration of that part of the sheet metal sections that is backed by the clamping means is counteracted by a force great enough to deform the sheet metal sections. This results in an uneven section joint, which is most undesirable, especially in air craft assembling where the demands for even surfaces are high.
The main object of the invention is to provide an improved riveting device of the above type in which the clamping means arranged on the rivet bucking side of the sections to be assembled has such inertial properties that an undesirable deformation of the structure sections is avoided.
This is accomplished by the characteristic feature of the invention recited in the claims.
Further objects and advantages of the invention will appear from the following description and claims.
Embodiments of the invention are hereinbelow described in detail under reference to the accompanying drawings.